Field of the Invention
The present invention relates to an electrostatic discharge (ESD) circuit and a liquid crystal display (LCD) device including the same.
Discussion of the Related Art
LCD devices are suitable as a display device for televisions (TVs) and portable devices because the LCD devices are easily manufactured due to the advance of manufacturing technology and realize drivability of a driver, low power consumption, and a high-quality image. The LCD devices adjust a transmittance of light passing through a liquid crystal layer of a pixel according to an image signal input from the outside to display an image based on the image signal.
The LCD devices include a liquid crystal panel, in which a plurality of pixels are arranged in a matrix type and which displays an image, and a driving circuit unit that supplies signals and power for driving the liquid crystal panel.
When static electricity or an overvoltage is supplied to a pixel, the pixel and a line are broken down, and for this reason, the LCD devices cannot normally display an image. In order to overcome a problem caused by an inflow of the static electricity or the overvoltage, a data line and a gate line are connected to an ESD circuit in parallel.
A general antistatic circuit limits an overvoltage input from the outside, and diverts an overvoltage current, thereby protecting a thin film transistor (TFT) array. In the antistatic circuit, an operation of a panel should not be affected by voltage drop or a static current which occurs in the operation of the panel. On the other hand, when an overvoltage based on static electricity occurs, a turn-on time should be fast because a resistance of the antistatic circuit is low.
When static electricity occurs, an ESD circuit disperses the static electricity, thereby protecting a TFT array in an active area. When high-voltage static electricity occurs, the antistatic circuit first senses an electrostatic signal, and diverts an overvoltage current to a ground (GND) or a common voltage (Vcom) terminal.